Pulp screen



1932- w. R. TIDMARSH 11,874,834

PULP SCREEN Filed July 17, 1951 s Sheets-Sheet 1 INVENTORWILUAMRTIDMARSH yga fi d ATTORNEY iii-Ange: 3 1932 w. "R; TIDMARSH PULPSCREEN Filed July 1'7, 1951 3 Sheets-Sheet 2.

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INVEN T OR WILUAMRTIDMARSH W. R. TIDMARSH PULP SCREEN Filed July 17,1951 3 Sheets-Sheet 3 ATTORNEY Aug. 30, 1932.

B 5 Q 3 mm 2 mg m:

Patented Aug. 30, I 1932 WILLIAM R. mrnmmsn, or MONTREAL, QUEBEC, CANADAApplication filed July 17, 1am. seiiaino. 551.4 7. v

This invention relates to pulp screens used inthe manufacture of pulpand paper prod-V uctsand particularly to flat screens equipped with camoperated diaphragms arranged beneath the screen plates.

The purpose of the invention is "to :pro-

vide a generally improved and more compact assembly in which: thediaphragm is carried by a metal frame and thecam shaft.

is positioned close to the underside of the diaphragm in bearingsforming part of said frame. This revised assembly permits'the cam shoefittings'to bema'de shorter and more resistant to deflection thanheretofore and it also reduces deflection of the cam shaft Ibyadequately supporting the shaft throughout its length in bearings rigidwith the dia phragm frame. It also lends itself to the use of adesirable arrangementof coi'lsprings 26 for holding the cam shoestoth'eco-operati-ng cams and has other mechanicalsadvantages not foundinthe ordinary assembly. 1 In accordance with this invention, thediaphragm is attached to'wooden strips inlaid;

in the upper portion of ametal 'framewhich is clamped or otherwisesecured to the bottom of the screen vat, said frame being cast withsuitable passagesfor discharging the screened pulp from thespace'reserved be tween the screen plates and the underlying diaphragm.The camshaft is carried in a sectional bearing comprising anupper'portion integral with the metal diaphragm frame and a lowerportion consisting of separate sections bolted to the upper portion. The

cam shoes are attached to metal fittingsat the underside of thediaphragm'and the'upper portion of the cam shaft bearing isprovided withcam shoe receiving slots located directly above the cams carried by theshaft.

The cam shoe fittings and the upper portion of the shaft hearing areprovided with slid-' ably engaging surfaces serving to" resist v sentingvertical portions -19 merging witht'he side walls'loand'horizontalportions 20 merg 95 lateral deflection of the cam shoes and areconnected together by spring connections arranged to hold the cam shoesto thecooperatingcams.

Proceeding now to a more detailed -discussion of the invention"reference will be had to the accompanying "drawi-ngs 'in wh ch;

cordance with this invention. 7

Fig. 1 is a longitudinal *sectional view I through a'screen' assemblyconstructed ina'c- Fig. 2 is a transverse sectional view along theline22ofFigL-l.

, Fig.8isa lan view'of the metaldi-aphragm' frame.

' Fig. 4 'is a side frame.

Fig. 5 is-an end view. of the diaphragm 50" frame. i Fig. 6 is asectional view along the line {View of thediaphragm 6-6of Fig. 3; p

Fig. 7 is asectiona-l view alongthe line 1 7- 7 of Fig. V I V Fig. -8 isa sectional view alongthe line 88 of Fig.3. g

' Fig". 9 is a sectional view along the line 9 9 of Fig.3.

Fig. 10 is a sectional view alongl the line 10-10 of Fig. i 1 a Fig. 11is an enlarged plan view of a poi :tBion ofthe diaphragm frame appearingig. 1. I v 7 "Fig. 12 is aside viewiof one of the 'cam75 shoe fittings.I 1 M Fig. 13 is a bottom plan viewof the fitting shown in Fig. 12. YFig. 14' isa cam shoes;

Fig. 15 is a side view of the camshaft. In these drawings the ordinaryscreen vat appears at 11 and is provided with theusual arrangement ofscreen plates '12. The diaperspective view of one of the phragm 1.3 isattached to wooden strips-14 5 v inlaid in the upper portion of themetallic diaphragm frame 15. The marginalportion ingwith the side wallflanges 16m] The lon gitudinal strips 14 to whichithe diaphragm 1-3 issecured are mountedon the flanges 1611 while the transversestrips '14are mounted on the flanges-17a and on the horizontal por llw tions 20 ofthe cross members; all of the strips 14 being bolted in place asindicated at 21 in Figs. 1 and 2 and having their upper surfaces flushwith the upper edges of the walls 16 and 17.

The frame 15 is cast with a plurality of passages 23 for conductingscreened pulp from the space between the screen plates and the diaphragmto the inlet 24 of the usual pulp receiving vat 25. The outer end ofeach passage communicateswith the vat inlet 24 through an opening 26in'one of the sidewalls 16 while the inner end of said passagecommunicates with the spacebetween the screen a,

plates and the diaphragm through an opening27 'in the adjacent flange16a. At the upper surface of the flange eachopening 27 is bounded byvertical side and end walls 28 and 29 forming a supplementary passageleading from the opening27 to a similar opening 30 in the diaphragm 13.

The cam shaft 31 carries the usual earns 32 and is journall ed in abearing comprising an suitable stiffening flanges 33a.

0 ing sections 33 and 34 are formed with mating -;operating with, thecam 32.

upper section 33 and a plurality of lower sections 34 boltedtogether'asindicated at 36. The upper section '33 is cast integral with the endwalls and cross members of the frame 15 and is reinforced at thesemembers by The bearhalf casings 33b and 34b affording housings enclosingthe cams 32. The upper portion 33b of eachcam housingis provided with aslot 37 for the entrance of a cam shoe 38 co- Each shoe .38 is carriedby a metal fitting comprising abase plate 39 provided with dependingsideflanges 40 and with a depending transverse rib 41, the latter extendingacross the-central portion ofthe plate between the side flanges. Thebase plate 39 is secured by bolts 42 to the usual oak plate 43 engagingthe lower side of the diaphragm 13 and the cam shoe' '38 ,issecuredtotheplate by bolting the shoe to'one side of the rib 41 as indicated at44.

A pair of spring sockets 45 are cast integral with the upper half 33?)of each cam housing andare arranged at opposite sides of the cam shoereceiving slot. 37. The spring sockets are closed at their upper endsexcept for' smallopenings 46 through which extend bolts 47 having theirupp'er ends fastened to the plate 39 asindicated at 48. The lower ends-of these bolts are equipped with nuts 50, supporting washers 51 fittedin the lower ends of the spring sockets, I Coil springs 52 are arrangedin said sockets to exert downward pressure on the washers 51 so that thecam shoes .38 are thereby held down upon the co operating cams 32. I I 1At the sides remote from the intervening slot 37 the spring sockets 45are provided with fiat surfaces '53 disposed in sliding enr 'gagementwith'suitable guide pedestals 54 depending from the plate 39. Thesliding engagement thus obtaining between the spring sockets and thepedestals constrains the guide shoe to a straight line vertical movementand thereby practically eliminates lateral deflection of the shoe. -Thebottom portion of the frame 15 may beprovided, as i shown in Fig. 2,with suitable inwardly direoted base flanges 56 adapted to be securedupon the upper ends of the supporting legs 57 In the present instancethe supporting legs 57 are shown as made of concrete but it will-beunderstood that the usual metal supp ortinglegs may be substituted ifdesired.

The diaphragm frame 15 may be clamped or detachably secured to thebottom of the screen vat 11 in any desired manner.

diaphragm is attached. This arrangement also brings the shaft close tothe underside of the diaphragmsothat the cam shoes may be directlyattached to short depending'ribs. carried by a metal. plate at theunderside of the diaphragm withthe result that the cam shoe fitting thusprovided is more rigid and resistant to lateral flexure than therelatively long cam shoe fittingsrequired inthe conventional assembly,wherein the'cam shaft is positioned an appreciable distance below thediaphragm. The mounting of the cam shaft close to the underside of thediaphragm also enables the cam shoevflttings and the shaftsupportingframe to be interconnected in a convenient and desirablemanner to hold the cam shoes to the coeoperating cams and toassist inpreventing lateral motion or deflection of the shoes.

Having thus described my invention, what I claim is f 1. A screenassembly of the character dethe present instance. Ihave shownconvenscribed including a screen vat, a diaphragm' 7 frame beneath thescreenvat, a diaphragm attached to said frame, a oamshaft jour nalled inthe frame beneath the diaphragm, and .cam shoes. depending from thediaphragm and engaging co-operating cams on saidshaft. a a H 2. A screenassembly of the character described including a screen vat, a metaldiaphragm frame beneath the vat, a diaphragm carried by said frame, acam shaft jour-. nalled in the frame beneath the diaphragm,

cam shoes depending from the diaphragm and engaging co-operating cams onsaid shaft, and means for exerting resilient pressure on the shoes inthe direction of the cams.

3. A screen assembly of the character described including a screen vat,a metal diaphragm frame beneath the vat, a diaphragm carried by theframe, a cam shaft journalled in the frame beneath thediaphragm, cam

shoes depending from the diaphragm and engaging co-operating cams onsaid shaft, and means rigid with the cam shoes and engag- '-ing theframe to resist lateral displacement scribed including a screen vat, ametal diaof the shoes.

4. A screen assembly of the character dephragm frame beneath the vat, adiaphragm carried by said frame, a cam shaft journalled in theframebeneaththediaphragm,camshoes depending from the diaphragm andengaging co-operating cams on said shaft, means for exerting resilientpressure on the shoes in .the direction of the cams and means rigid I'with the cam shoes and engaging the frame to resist lateral displacementof the shoes.

5. A screen assembly of the character de scribed including a screen vat,a diaphragm frame beneath the vat, a diaphragm carried by the frame, acam shaft journalled in the frame below the diaphragm, cam shoe fittingsat the underside of the diaphragm, cam shoes depending from the fittingsand engaging ,co-operating cams on said shaft, and

spring connections between the frame and the cam shoe fittings servingto hold the shoes engaged with said cams. I 6. A screen assembly of thecharacter described including a screen vat, a diaphragmframe beneath theVat, a diaphragm carried by the frame, a cam shaftjournalled in theframe beneath the diaphragm, cam shoe fittings at the underside of thediaphragm and v cam shoes depending from the fittings and engagingco-operating cams on the shaft,

said cam shoe fittings having portions slidably engaging co-actingportions on the frame to resist lateral displacement of the cam shoes.

7. A screen assembly of the character described including a screen vat,a diaphragm frame beneath the vat, a diaphragm carried by the frame, acam shaft journalled in the frame below the diaphragm, cam shoe fittingsat the underside of the diaphragm,

cam shoes depending from the fittings and engaging co-operating cams onsaid shaft, said cam shoe fittings having portions slidably engagingco-acting portions on the frame to resist lateral displacement of thecam shoes and spring connections between the frame and the cam shoefittings serving to hold the shoes engaged with said cams.

the cam shaft, said bearing structure combearing sections detachablysecured to the upper sectlon, said upper. section being' formed toprovide half casings mating with similar half casings of the lowersections to provide housings for enclosing the cams carried by saidshaft, each housing having a slot in theupper half for the passage of,the

co-operating cam'shoe'attached to the; diaphragm.

In witness whereof, I have hereunto setmy hand. 7

WILLIAM R, TIDMARSH.

8. A metal diaphragm frame for screen vats equipped with a bearingstructure for

